Releasable closure mechanism

ABSTRACT

This releasable closure comprises a butterfly spring separating a base plate and a movable weight that are coaxial and have interspersed fingers on the peripheries thereof. A first loose garter spring is located completely in first annular grooves in the peripheries of the plate fingers and under first lands on the weight fingers to keep the plate and weight axially spaced apart. A second tight locking ring spring is located in second annular grooves in the plate fingers and on second lands on the weight fingers. The second spring extends beyond the peripheries of the base plate and weight and protrudes into a mating groove in a vehicle to hold the closure securely therein. Forward motion and rotation of the vehicle and closure causes the loose spring to be ejected. Upon impact with the ground, forward movement of the weight compresses the butterfly spring and causes the second spring to slip off the second lands and completely into the second grooves to release the closure and a self-erecting antenna in the vehicle.

United States Patent Hansen 1 June 13, 1972 [54] RELEASABLE CLOSURE MECHANISM Harvey Gordon Hansen, Sunnyvale, Calif.

[73] Assignee: Sylvania Electric Products Inc.

[22] Filed: Jan. 4, 1971 [21] Appl. No.: 103,619

[72] Inventor:

Primary ExaminerM. Henson Wood, Jr. Assistant ExaminerMichael Y. Mar Att0rneyNorman J. OMalley, Russell A. Cannon and John F. Lawler ABSTRACT This releasable closure comprises a butterfly spring separating a base plate and a movable weight that are coaxial and have interspersed fingers on the peripheries thereof. A first loose garter spring is located completely in first annular grooves in the peripheries of the plate fingers and under first lands on the weight fingers to keep the plate and weight axially spaced apart. A second tight locking ring spring is located in second annular grooves in the plate fingers and on second lands on the weight fingers. The second spring extends beyond the peripheries of the base plate and weight and protrudes into a mating groove in a vehicle to hold the closure securely therein. Forward motion and rotation of the vehicle and closure causes the loose spring to be ejected. Upon impact with the ground, forward movement of the weight compresses the butterfly spring and causes the second spring to slip off the second lands and completely into the second grooves to release the closure and a self-erecting antenna in the vehicle.

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sum 3 or 3 FII:EI ILIII HARVEY GORDON HANSEN INVENTOR.

RELEASABLE CLOSURE MECHANISM BACKGROUND OF INVENTION This invention relates to a mechanism for closing a receptacle and restraining apparatus therein and for opening the receptacle under specified conditions for releasing the apparatus therein.

In military operations it is frequently desirable to know when there is movement of enemy troops, even in remote areas and behind their own lines of defense. The classical technique for maintaining surveillance of an area is by direct observation. Personnel are deployed into the area to watch for and radio information on troop movements to a command post. There is always the danger that the deployed personnel will either be captured or killed by the enemy. An alternate technique is to drop a vehicle containing electronic equipment into the area. After the vehicle implants itself in the earth the electronic equipment is automatically activated, senses activity in the area, and transmits information to the command post. One of the problems with such equipment is that the vehicle must be automatically opened so that a radio antenna can be erected on the vehicle before the electronic equipment will function properly. A prior art technique for releasably sealing a vehicle for holding a self-erecting antenna in it is to secure a closing cap in the open end of the vehicle with an explosively energized bolt. An explosive charge in the bolt is detonated to release the bolt, cap and antenna. This technique has an undesirable feature in that detonation of the explosive charge may be heard by and alert enemy personnel in the area that is under surveillance. Also, this technique is dangerous in that the explosive charge may be detonated during handling and injure ones own personnel while they are transporting the vehicle.

An object of this invention is the provision of an improved closure mechanism overcoming these undesirable features.

DESCRIPTION OF DRAWINGS FIGS. 1, 2 and 3 are perspective views of a releasable closure mechanism embodying this invention;

FIG. 4 is a top view ofthe base plate in FIG. 1;

FIG. 5 is a section view taken along lines 5-5 in FIG. 4;

FIG. 6 is a section view of the movable weight in FIG. 1;

FIG. 7 is a section view taken along lines 7-7 in FIG. 6;

FIG. 8 is a perspective view of a butterfly spring in the closure MECHANISM IN FIGS. 1-3;

FIG. 9 is an enlarged fragmentary view, partially cut away, of the top of a vehicle utilizing this invention;

FIG. 10 is a perspective view of a vehicle in flight and utilizing this invention;

FIG. 11 is an enlarged fragmentary view, partially cut away, of the top of a vehicle utilizing this invention during implant of the vehicle in the ground; and

FIG. 12 is a perspective view of a self-erecting antenna that is automatically extended from a vehicle after the latter is implanted in the ground.

DESCRIPTION OF PREFERRED EMBODIMENTS A releasable closure mechanism embodying this invention is illustrated in FIGS. 1-3. The mechanism in FIG. 1 is in position for maintaining a receptacle closed in a manner that is described more fully hereinafter in relation to FIGS. 9-12. In FIG. 2, the mechanism is armed so that it may be activated and released from the receptacle. In FIG. 3, the mechanism is shown in the activated position which enables it to be released from the receptacle. Referring now to FIG. 1, the closure mechanism comprises a base plate 5, movable weight 6, locking ring 7, garter spring 8 and retainer ring 9. Top and section views of base plate 5 are illustrated in FIGS. 4 and 5, respectively. Similarly, top and section views of the movable weight 6 are illustrated in FIGS. 6 and 7, respectively.

Base plate 5 comprises a flat disc section 12 supporting a center post 14 and upwardly extending fingers Isa-15f formed on the periphery thereof (see FIGS. 4 and 5). The

inner and outer faces of fingers 15 are coaxial with center post 14. A groove 16 is formed near the top of the center post for receiving retainer ring 9. The fingers 15 are evenly spaced about the circumference of disc 12 with openings therebetween. Annular grooves 19 and 21 are formed by lands 18 and and lands 20 and 22, respectively, on the periphery of fingers 15.

. Movable weight 6 also comprises a flat disc section 25 having six downwardly extending fingers 26a-26f formed on the periphery thereof (see FIGS. 6 and 7). Disc 25 has a coaxial center hole 27 and opening 28 therein for receiving post 14 and retainer ring 9, respectively. The inner and outer faces of fingers 26 are coaxial with center hole 27. The fingers 26 are also evenly spaced about the circumference of disc 25 with openings therebetween, the fingers on discs 12 and 25 being dimensioned so that the fingers on one disc fit smoothly into the openings between the fingers of the other disc and vice versa when the closure mechanism is assembled as illustrated in FIG. 2. A wide annular groove 30 is formed by the lands 29 and 31 on the periphery of fingers 26.

The circumferences of lands 18, 20, 22 and 29 are preferably equal so that the assembled closure mechanism (see FIG. 3) will slide smoothly into an opening in a receptacle (not shown). The circumferences of the faces of grooves 19, 21 and 30 are also the same. The circumference of lands 31 is less than that of the other lands and greater than that of the grooves, however, so that locking ring 7 will protrude out past the periphery of plate 5 and weight 6 when this ring is positioned on land 31 (see FIG. 1). The thicknesses of lands 18 and 29 are substantially equal. The height A of weight fingers 26 is equal to the distance A between the tops of the fingers 15 and lands 22. The thickness of land 31, however, is approximately equal to the width of groove 21 and is less than the thickness of land 22. The inner diameters B and C of the fingers are slightly greater than the diameters B and C, respectively, of the discs so that the weight 6 slides smoothly over the base plate 5.

Locking ring 7 is very hard for resisting deformation under a shearing force. Ring 7 may be made of a rod of spring steel such as spring tempered 302 stainless steel. Locking rings are made by forming the rod into a series of convolutes of a prescribed diameter less than that of the grooves. The convolutes are then cut to make individual locking rings. The diameter of the rod forming ring 7 is slightly less than the depth of groove 21 and the difference between the diameters of lands 20 and 31. In contrast, spring 8 is sufficiently flexible that it may be distorted or squeezed in by a shear force, and that it expands when subjected to a centrifugal force of suffcient magnitude. The thickness of spring 8 is approximately equal to the depth of groove 19.

The closure mechanism is assembled by stacking the butterfly spring 34 (see FIG. 8), the moving weight (see FIG. 7) and retainer ring 9 on the center post 14 of base plate 5 (see FIG. 5) in that order. The locking ring 7 is then expanded and inserted over the lands 22 into groove 21. When the weight 6 is in the activated or extended position illustrated in FIG. 3, locking ring 7 is expanded with a special pair of pliers or a special tool (not shown) having thin fingers with tapered ends. The thin fingers slide down (as viewed in FIGS. 2 and 3) between adjacent fingers of the plate 5 and weight 6 for expanding ring 7 into a mating groove (not shown) of a receptacle. The tool is removed after weight 6 is pulled up so that the lands 31 are aligned with grooves 21 for supporting ring 7. The garter spring 8 is then expanded and placed in grooves 19 to prevent accidental downward movement of weight 6 which would allow ring 7 to slip off the lands 31 and release the closure mechanism. The butterfly spring 34 aids in maintaining the plate 5 and weight 6 in the spaced relationship illustrated in FIG. 2 when the garter spring 8 is removed.

In operation, the closure mechanism compresses a helical spring 36 for example in the opening 37 of a vehicle 38 and is secured in the end of the opening as described above (see FIG. 9). The locking ring 7 rests on lands 31 and is partially in both the grooves 21 of the closure and the groove 39 of the vehicle. Thus, ring 7 prevents the closure mechanism being ejected from the vehicle by the force exerted thereon by spring 36. Garter spring 8 prevents downward movement of weight 6 and release of the closure mechanism. An end cap 40 having a lip 41 thereon is lightly press fit into the end of the vehicle. The lip 41 holds the garter spring 8 in place during routine handling thereof and thereby prevents improper release of the closure mechanism and the contents of the vehicle.

When the vehicle 38 is forcefully launched from an aircraft for example the end cap 40 may be pulled loose. Alternatively, both end cap 40 and garter spring 8 may be separated from the vehicle 38 by the centrifugal force of the high spin rate that is induced in it to stabilize it in flight (see FIG. 10). During this portion of the vehicle's flight, the closure mechanism is armed as illustrated in FIG. 2. When the vehicle strikes the ground, the momentum of weight 6 exceeds and overcomes friction and the opposing force of butterfly spring 34 and the weight moves forward to its lower most position illustrated in FIG. 1 1. Locking ring 7 slips off lands 3] and is totally within the grooves 21. The closure mechanism is then held in the opening 37 of the vehicle by the momentum of the former which is greater than any opposing force exerted by the spring 36. When the vehicle finally comes to rest in the ground, spring 36 ejects the closure mechanism from the vehicle to allow a selferecting antenna 44, for example, in the vehicle to be erected (see FIG. 12).

Although this invention is described in relation to a specific embodiment thereof, modifications will occur to those skilled in the art. By way of example, the garter spring 8 may be manually released from the closure mechanism by milling a small slot 46 in a land 18 of a finger (see FIG. 4) and expanding the spring 8 by inserting a sharp-pointed instrument in slot 46 between this spring and the finger. Also, arcuate blocking segments or sections of a rod-convolute similar to spring 7 may be inserted in the grooves 19 in place of the garter spring 8. A coil or other type of spring device could also be substituted for the butterfly spring 34. The scope of this invention is therefore to be determined from the appended claims rather than from the preceding detailed description of a preferred embodiment thereof.

What is claimed is:

l. A mechanism for releasably closing an opening in an object comprising a base member having a body portion and a plurality of first fingers spaced apart on the periphery of said base body to form openings therebetween, the periphery of said base member being dimensioned and shaped to fit smoothly into the opening in the object, each of said first fingers having a first groove in the periphery thereof, all of said first grooves being aligned in a common plane,

a movable weight stacked on said base member and having a body portion and a plurality of second fingers spaced apart on the periphery of said weight to form openings therebetween, the periphery of said weight being dimensioned and shaped to fit into the opening in the object, each of said first weight fingers having a first land on the periphery thereof, all of said first lands being aligned in a common plane,

said base and weight fingers being dimensioned and spaced on associated bodies and oriented with the weight fingers fitting smoothly into the openings between the base fingets and vice versa,

the perimeter outlined by the periphery of said first lands being greater than that outlined by the faces of said first grooves and less than the periphery outlined by lands defining said first grooves, and

a locking ring spring located in said first grooves and having a thickness that is less than the depth of said first grooves,

said mechanism being armed for closing the opening in the object when said locking ring, first lands and first grooves are all aligned in the same common plane with the locking ring located on the eriphery of said first lands and only partially within sai first grooves, the periphery of said locking ring extending beyond the periphery of said first fingers and base member; said mechanism being actuated for release thereof from the opening in the object by moving said weight and first lands out of alignment with said first grooves for allowing said ring to slip into and be contained wholly within said first grooves.

2. The mechanism according to claim 1 including means for restricting movement of said weight in one direction and allowing for movement of said weight in the opposite direction.

3. The mechanism according to claim 2 wherein each of said first fingers has a second groove in the periphery thereof, all of said second grooves being aligned in a common plane, and each of said second fingers has a second land on the periphery thereof, all of said second lands being aligned in a common plane, the perimeter outlined by the periphery of said second lands being greater than that outlined by the faces of said second grooves, said second lands and lands defining said second grooves being aligned in a common plane when said locking ring is on said first lands in the first grooves for receiving in said second grooves means for restricting movement of said weight in said opposite direction.

4. The mechanism according to claim 3 wherein said bodies are substantially flat and parallel with the associated fingers substantially perpendicular thereto.

5. The mechanism according to claim 4 wherein the peripheries of said base member and said weight are substantially circular.

6. The mechanism according to claim 5 wherein said base and weight are oriented with the first and second fingers extending toward the weight body and base body, respectively.

7. The mechanism according to claim 6 including spring means located between said base and weight bodies for aiding in spacing said bodies apart. 

1. A mechanism for releasably closing an opening in an object comprising a base member having a body portion and a plurality of first fingers spaced apart on the periphery of said base body to form openings therebetween, the periphery of said base member being dimensioned and shaped to fit smoothly into the opening in the object, each of said first fingers having a first groove in the periphery thereof, all of said first grooves being aligned in a common plane, a movable weight stacked on said base member and having a body portion and a plurality of second fingers spaced apart on the periphery of said weight to form openings therebetween, the periphery of said weight being dimensioned and shaped to fit into the opening in the object, each of said first weight fingers having a first land on the periphery thereof, all of said first lands being aligned in a common plane, said base and weight fingers being dimensioned and spaced on associated bodies and oriented with the weight fingers fitting smoothly into the openings between the base fingers and vice versa, the perimeter outlined by the periphery of said first lands being greater than that outlined by the faces of said first grooves and less than the periphery outlined by lands defining said first grooves, and a locking ring spring located in said first grooves and having a thickness that is less than the depth of said first grooves, said mechanism being armed for closing the opening in the object when said locking ring, first lands and first grooves are all aligned in the same common plane with the locking ring located on the periphery of said first lands and only partially within said first grooves, the periphery of said locking ring extending beyond the periphery of said first fingers and base member; said mechanism being actuated for release thereof from the opening in the object by moving said weight and first lands out of alignment with said first grooves for allowing said ring to slip into and be contained wholly within said first grooves.
 2. The mechanism according to claim 1 including means for restricting movement of said weight in one direction and allowing for movement of said weight in the opposite direction.
 3. The mechanism according to claim 2 wherein each of said first fingers has a second groove in the periphery thereof, all of said second grooves being aligned in a common plane, and each of said second fingers has a second land on the periphery thereof, all of said second lands being aligned in a common plane, the perimeter outlined by the periphery of said second lands being greater than that outlined by the faces of said second grooves, said second lands and lands defining said second grooves being aligned in a common plane when said locking ring is on said first lands in the first grooves for receiving in said second grooves means for restricting movement of said weight in said opposite direction.
 4. The mechanism according to claim 3 wherein said bodies are substantially flat and parallel with the associated fingers substantially perpendicular thereto.
 5. The mechanism according to claim 4 wherein the peripheries of said base member and said weight are substantially circular.
 6. The mechanism according to claim 5 wherein said base and weight are oriented with the first and second fingers extending toward the weight body and base body, respectively.
 7. The mechanism according to claim 6 including spring means located between said base and weight bodies for aiding in spacing said bodies apart. 